A cellular telecommunications system is a communications system that is based on the use of radio access entities and/or wireless service areas. The access entities operate over respective coverage areas that are typically referred to as cells. In a cellular system, a base transceiver station provides a wireless communication facility that serves mobile stations (MS) or similar wireless user equipment (UE) via an air or radio interface within the coverage area of the cell. Examples of cellular telecommunications systems include standards such as GSM (Global System for Mobile communications) or various GSM based systems (such as GPRS (General Packet Radio Service)), AMPS (American Mobile Phone System), DAMPS (Digital AMPS), WCDMA (Wideband Code Division Multiple Access), UMTS (Universal Mobile Telecommunications System), CDMA 2000, and so on.
UMTS is a so-called third generation system expected to replace GSM soon. The third generation partnership project (3GPP) has been setting out aspects of the UMTS system. The 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations, to make a globally applicable third generation (3G) mobile phone system specification within the scope of the International Mobile Telecommunications-2000 project of the International Telecommunication Union (ITU).
Worldwide Interoperability for Microwave Access or WiMAX is a different telecommunications technology aimed at providing wireless data over long distances in a variety of ways; from point-to-point links to full mobile cellular type access. WiMAX provides the delivery of last mile wireless broadband access as an alternative to cable and DSL. The WiMAX Forum has defined an architecture that defines how a WiMAX network connects with other networks, and a variety of other aspects of operating such a network, including address allocation, and authentication.
In a telecommunications network, a mobile station is typically connected to a local network, which provides, among other things, radio connectivity. The local network also establishes a connection between the mobile station and a network where a variety of services (e.g., routing, Internet protocol routing, etc.) are provided.
FIG. 1 is a simplified diagram illustrating a conventional telecommunications network. As an example, the conventional telecommunications network as illustrated in FIG. 1 complies with WiMAX wireless networks.
As shown in FIG. 1, the mobile station MS, which is sometimes referred to as mobile subscriber station SS when the mobile station MS is subscribed to a specific network service provider, is connected to an access service network. For example, the MS is connected to the access service network (ASN). For example, the ASN is configured to provide radio access to the mobile station. The ASN may include a base station (BS) for providing radio access. For example, the BS refers to generalized equipment set for providing connectivity, management, and control of mobile stations. In addition, the ASN includes a gateway (ASN GW) for interfacing with other networks. For example, the gateway allows the mobile station 101 to communicate with other ASNs (e.g., another ASN). As another example, the gateway allows the mobile station to connect to a connectivity service network (CSN), which may also include a Home Agent HA. As an example, the connectivity service network refers to a set of network functions that provide, among other things, IP connectivity service to mobile stations. Often, the CSNs also store policies associated with mobile stations, and includes an Authentication, Authorization and Accounting (AAA) Server. NAP is a Network Access Provider that includes the ASN.
Typically, a mobile station connects to a CSN that stores the network policies associated with the mobile station through an ASN. As an example, the CSN is often referred as a network service provider from a management perspective. Similarly, the ASN is often referred to as a network access provider from a management perspective. Typically, the ASN and/or the CSN stores information associated with individual wireless devices. As an example, the information includes location information of a specific wireless device. As another example, the information includes context information for a wireless device. NSP is a Network Service Provider that also includes the CSN.
A number of components (not all shown), plus some of the interconnections (or reference points) between these, labeled R1 to R5 and R8 are defined by the WiMAX forum.
Conventional wireless networks do not function seamlessly when a wireless device moves and/or enters into a geographical location serviced by a different type of wireless network or if a wireless device accesses multiple types of networks simultaneously.
Hence, what is needed are methods and systems to enable interworking between different networks (e.g., 3GPP and WiMax) without significant service interruption and impact performance of UE and/or network.